title: Differences in ventriculoatrial intervals during entrainment and tachycardia: a simpler method for distinguishing paroxysmal supraventricular tachycardia with long ventriculoatrial intervals.
abstract: BACKGROUND
  Usefulness of the interval between the last pacing stimulus and the last entrained atrial electrogram (SA) minus the tachycardia ventriculoatrial (VA) interval in the differential diagnosis of supraventricular tachycardias with long (>100 ms) VA intervals has not been prospectively studied in a large series of patients. Our objective was to assess the usefulness of the difference SA-VA in diagnosing the mechanism of those tachycardias in patients without preexcitation. The results were compared with those obtained using the corrected return cycle (postpacing interval-tachycardia cycle length-atrioventricular [AV] nodal delay).
  
  
  RESULTS
  We included 314 consecutive patients with inducible sustained supraventricular tachycardias with VA intervals >100 ms undergoing an electrophysiologic study. Atrial tachycardias were excluded. Tachycardia entrainment was attempted through pacing trains from right ventricular apex. The SA-VA difference and the corrected return cycle were calculated for every patient. Electrophysiologic study revealed 82 atypical AV nodal reentrant tachycardias (AVNRT) and 237 AV reentrant tachycardias (AVRT) using septal (n = 91) or free-wall (n = 146) accessory pathways (APs). A SA-VA difference >110 ms identified an atypical AVNRT with sensitivity, specificity, positive and negative predictive values of 99%, 98%, 95%, and 99.5%, respectively. Similarly, these values were 88%, 83%, 77%, and 92% for SA-VA difference <50 ms in identifying AVRT through a septal versus free-wall AP. The SA-VA difference showed higher accuracy in septal AP identification than that obtained using the corrected return cycle.
  
  
  CONCLUSIONS
  The difference SA-VA provides a simpler electrophysiologic maneuver that reliably differentiates atypical AVNRT from AVRT regardless of concealed AP location.
authors.affiliation: Cardiology Department, Hospital General Universitario Gregorio Marañón, Madrid, Spain. etorrecilla@telefonica.net
authors.forename: Esteban
authors.initials: E
authors.lastname: González-Torrecilla
authors.forename: Jesús
authors.initials: J
authors.lastname: Almendral
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: García-Fernández
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Arias
authors.forename: Angel
authors.initials: A
authors.lastname: Arenal
authors.forename: Felipe
authors.initials: F
authors.lastname: Atienza
authors.forename: Tomás
authors.initials: T
authors.lastname: Datino
authors.forename: Leonardo F
authors.initials: LF
authors.lastname: Atea
authors.forename: David
authors.initials: D
authors.lastname: Calvo
authors.forename: Marta
authors.initials: M
authors.lastname: Pachón
authors.forename: Francisco
authors.initials: F
authors.lastname: Fernández-Avilés
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001283:Atrioventricular Node / Q000502:physiology*; D002304:Cardiac Pacing, Artificial / Q000379:methods; D002648:Child; D002675:Child, Preschool; D005260:Female; D006329:Heart Conduction System / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013614:Tachycardia, Paroxysmal / Q000175:diagnosis* / Q000503:physiopathology* / Q000628:therapy; D013617:Tachycardia, Supraventricular / Q000175:diagnosis* / Q000503:physiopathology* / Q000628:therapy; D013997:Time Factors; D055815:Young Adult